Question: What is the safety classification of nitrogen dioxide with a NFPA Health label of 3?
Paraphrase: If nitrogen dioxide has a NFPA label of 3, what is it's safety classification?
SPARQL (Wikidata): SELECT ?obj WHERE { wd:Q207895 p:P4952 ?s . ?s ps:P4952 ?obj . ?s pq:P993 ?x filter(contains(?x , '3')) }